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A = 6/19 . -7/11 + 6/19 . -4/11 + -13/19
A = 6/19 . [-7/11 + (-4/11)] + (-13/19)
A = 6/19 . -11/11 + (-13/19)
A = 6/19 . (-1) + (-13/19)
A = -6/19 + (-13/19)
A = -19/19
A = -1
Vậy A = -1
\(A=\dfrac{6}{19}.\dfrac{-7}{11}+\dfrac{6}{19}.\dfrac{-4}{11}+\dfrac{-13}{19}\)
\(A=\dfrac{6}{19}.\left(\dfrac{-7}{11}+\dfrac{-4}{11}\right)+\dfrac{-13}{19}\)
\(A=\dfrac{6}{19}.-1+\dfrac{-13}{19}=\dfrac{-6}{19}+\dfrac{-13}{19}=\dfrac{-19}{19}=-1\)
B=57.−413+57.73−513.37
B=57.−413+57.73− \(\dfrac{5}{7}.\dfrac{3}{13}\)3
7
\(B=\dfrac{5}{7}.\left(\dfrac{-4}{13}+\dfrac{7}{3}-\dfrac{3}{13}\right)\)
\(B=\dfrac{5}{7}.\dfrac{70}{39}=\dfrac{350}{273}\)
Câu B ko rõ lắm
\(B=\dfrac{5}{7}.\dfrac{-4}{13}+\dfrac{5}{7}.\dfrac{7}{3}-\dfrac{5}{13}.\dfrac{3}{7}\)
\(B=\dfrac{5}{7}.\dfrac{-4}{13}+\dfrac{5}{7}.\dfrac{7}{3}-\dfrac{5}{7}.\dfrac{3}{13}\)
Rồi tiếp 2 câu rõ
Gợi ý: Sử dụng tính chất phân phối của phép nhân đối với phép cộng để nhóm thừa số chung ra ngoài.
a: \(=\dfrac{8}{9}\cdot\dfrac{9}{4}\cdot\dfrac{12}{19}\cdot\dfrac{19}{24}=\dfrac{1}{2}\cdot2=1\)
b: \(=\dfrac{5}{16}\cdot\dfrac{17}{15}\cdot\dfrac{8}{17}=\dfrac{5}{16}\cdot\dfrac{8}{15}=\dfrac{40}{240}=\dfrac{1}{6}\)
c: \(=\dfrac{4}{13}\left(\dfrac{2}{7}+\dfrac{5}{7}\right)-\dfrac{3}{26}=\dfrac{4}{13}-\dfrac{3}{26}=\dfrac{5}{26}\)
c: \(=\dfrac{3}{4}\left(\dfrac{6}{11}+\dfrac{5}{11}\right)-\dfrac{1}{5}=\dfrac{3}{4}-\dfrac{1}{5}=\dfrac{11}{20}\)
\(=\left[\dfrac{12}{7}\cdot\left(19+\dfrac{5}{8}-13-\dfrac{1}{4}\right)\right]\cdot\dfrac{4}{5}\)
\(=\dfrac{12}{7}\cdot\dfrac{51}{8}\cdot\dfrac{4}{5}=\dfrac{306}{35}\)
g: \(=\dfrac{-3}{4}-\dfrac{1}{4}+\dfrac{5}{7}+\dfrac{2}{7}+\dfrac{3}{5}=\dfrac{3}{5}\)
h: \(=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)-\dfrac{12}{19}=\dfrac{7}{19}-\dfrac{12}{19}=-\dfrac{5}{19}\)
i: \(=\dfrac{2013}{7}\left(19+\dfrac{5}{8}-26-\dfrac{5}{8}\right)=\dfrac{2013}{7}\cdot\left(-7\right)=-2013\)
\(P=\dfrac{1+19+\dfrac{19}{13}+\dfrac{19}{101}}{7+\dfrac{7}{13}+\dfrac{7}{19}+\dfrac{7}{101}}\)
\(=\dfrac{19\left(1+\dfrac{1}{3}+\dfrac{1}{19}+\dfrac{1}{101}\right)}{7\left(1+\dfrac{1}{13}+\dfrac{1}{19}+\dfrac{1}{101}\right)}=\dfrac{19}{7}\)
c,
= \(\dfrac{5}{9}.\left(\dfrac{7}{13}+\dfrac{9}{13}+\dfrac{-3}{13}\right)\)
= \(\dfrac{5}{9}.1\)
= \(\dfrac{5}{9}\)
a: =9+7=16
b: =11+3/13-2-4/7-5-3/13
=4-4/7
=28/7-4/7=24/7
c: =2/7(5+1/4-3-1/4)=2/7x2=4/7
Ta có: \(\dfrac{7}{13}\cdot\dfrac{5}{9}+\dfrac{7}{19}\cdot\dfrac{8}{13}-3\cdot\dfrac{7}{19}\)
\(=\dfrac{7}{13}\cdot\dfrac{5}{9}+\dfrac{7}{13}\cdot\dfrac{8}{19}-3\cdot\dfrac{7}{19}\)
\(=\dfrac{7}{13}\left(\dfrac{5}{9}+\dfrac{8}{19}\right)-3\cdot\dfrac{7}{19}\)
\(=\dfrac{7}{13}\cdot\dfrac{167}{171}-\dfrac{51}{19}\)
\(=\dfrac{-4798}{2223}\)
713⋅59+719⋅813−3⋅719
713⋅59+719⋅813−3⋅719
=713⋅59+713⋅819−3⋅719
=713⋅59+713⋅819−3⋅719
=713(59+819)−3⋅719
=713(59+819)−3⋅719
=713⋅167171−5119